Instructions

1. To make Crust, in bowl of a food processor fitted with steel blade attachment, pulse flour, icing sugar and salt. Scatter butter over dry ingredients and pulse 8 to 10 times until butter is coarsely cut in. Add whole egg and process in long pulses, about 10 seconds each, until dough comes together in large clumps. Turn out dough onto a clean work surface and very sparingly knead just to incorporate any dry ingredients that might have escaped mixing. Form into a disc, wrap in plastic wrap and chill in refrigerator for 2 hours.
2. With butter or cooking spray, lightly grease a 9-in (23 cm) fluted tart pan with a removable bottom.
3. On a lightly floured sheet of parchment, roll out chilled dough into a 16-in (40 cm) round, lifting and turning dough occasionally to free from paper. Using paper as an aid, turn dough into prepared tart pan before peeling off paper. Press dough into corners and seal any cracks in dough. Trim overhang to ½-in (1.25 cm). Fold in overhang, making double-thick sides. Pierce crust all over with fork. Freeze for at least 30 minutes.
4. Preheat oven to 375 F (190 C).
5. Coat shiny side of a piece of foil with butter or cooking spray, then place it, buttered-side down, tightly against frozen crust. Put tart pan on a baking sheet and bake crust for 20 minutes. Carefully remove foil. If crust has puffed, press it down gently with back of a spoon. Bake for another 5 to 10 minutes, until firm but still pale.
6. While crust finishes baking, whisk egg yolk in a small bowl and set aside.
7. Once crust is baked, transfer tart pan to a rack, brush inside crust with a light coating of egg yolk and allow to cool at room temperature.
8. Reduce oven temperature to 350 F (175 C).
9. To make Frangipane Filling, in bowl of a stand mixer fitted with paddle attachment, cream butter, sugar, vanilla and cinnamon until pale and creamy, about 4 minutes. Add eggs 1 at a time, beating well after each. Remove bowl from machine. Add all-purpose and almond flours and incorporate with a wooden spoon. Spread filling evenly over base of crust. Top with halved grapes and sprinkle with almonds.
10. Bake until filling is puffed and set, 40 to 45 minutes. Place on a rack to cool to room temperature.
11. To make Topping, in a small saucepan, combine honey and grappa and place over medium-high heat. Bring to a simmer, stirring constantly. Simmer for 5 minutes, then remove from heat and set aside to cool to room temperature.
12. To serve, artfully arrange grape clusters over tart and drizzle with some grappa honey. Slice into wedges and serve.